Method and composition for preventing corrosion



July 9, 1963 w. s. WHITE, JR., r-.TAL 3,096,819

METHOD AND COMPOSITION FOR PREVENTING CORROSION Filed May 22, 1959 /nVen fari.

UnitedStates Patent O 3,096,819 METHOD AND COMPUSlTION FR PREVENTINGCORROSION William S. White, Jr., Midland, and Jackson L. Babb and JohnH. McGuire, Odessa, Tex., assignors to Champion Chemicals, Inc., Odessa,Tex., a corporation of Texas Filed May 22, 1959, Ser. No. 815,195 3Claims. (Cl. 166--1) This Iinvention pertains tto corrosion preventionand more particularly to the petroleum industry and the prevention ofcorrosion in gas carrying lines and wells.

In the petroleum industry a problem exists with oorrosion. Advances havebeen made toward the prevention of corrosion with liquid petroleum bythe introduction of certain polar or iilming amines. These corrosionininhibiting amines may -be introduced into the liquid petroleum and asthey have an ainity for metal they will seek the metal surfaces and forma single molecular coating thereon. Periodically additional inhibitormay be introduced into the liquid to maintain the coating intact. In thecase of wells the coating may be introduced into the well by variousback-washing techniques or otherwise.

However; this procedure is not adapted to petroleum in a gaseous state.The inhibitors are normally in a solid or liquid state. If the conduitcarrying the gas were hozontal, liquid in the line would form a streamalong the bottom of the line and not Contact the remainder of theinterior of the line fand therefore not coat it. If the conduit werevertical, as in the case of la well, it would not be practical to coatit in this manner.

An object of our invention is to prevent the corrosion of gas carryingconduits.

Another object is to provide a method for coating the interior ofconduits carrying gases, said coating being introduced as the conduit isin use.

Another object of our invention is to provide Ia composition ofmaterials adapted to be introduced into the normal gas stream of a gascarrying conduit while in use for the purpose of coating the interiorthereof.

Further objects are to achieve the above in a manner that is simple landreliable, not requiring fragile or bulky equipment, yet is inexpensiveand easy to operate.

T-he speciiic nature of the invention as well as other objects, uses,and advantages thereof will clearly appear from the followingdescription and the accompanying drawings in which:

FIG. 1 is a schematic representation of a gas well using one form ofthis invention.

FIG. Z is a schematic representation of a gas well using a second form.

As may be seen in the accompanying drawings, one specific embodiment ofthis invention pertains to the protection of production string A whichextends within a lWell B from the surface to gas bearing sand C, farbeneath the surface.

As stated above, the problem is that the gas in the gas bearing sandscontains corrosive substances such as carbon dioxide or hydrogensulfide. There exists today certain corrosion inhibiting materials whichare well adapted to prevent corrosion `of the production string A bythese substances. An example of such materials is a product of ChampionChemical, Inc. known by its trademark Cortron which is a `form of apolar lming amine. More specifically, the polar iilming lamine may bedescribed' as a primary, secondary, or tertiary amine in form ofaliphatic or cyclic molecules containing one or more amine 3,096,819Patented July 9, 1963 ice groups, normally neutralized with some typehigh molecular weight organic acid. Such polar filming amines aredisclosed in lU.S. Patent No. 2,856,211.

To get these rust inhibitors upon the inside surface of the productionstring, we insert tube l10 of small diameter within the productionstring. This tube extends to nozzle =12 at the bottom of the productionstring. Spacer 14 centers the nozzle within the pipe or string. Liquidinhibitor is introduced at the surface of the ground into the tube 10.The inhibitor may be mixed with diluents or vehicles. The hydrostatichead of the fluid in the tube sometimes will be sufcient to cause it toatomize or break into a very ne spray or mist when it is ejected fromthe nozzle 12. At other times la pump will be necessary to obtain thepressures necessary. The mist is carried upward by the gas beingproduced by the well so that it has an opportunity to come in contactwith the surface of the conduit. If it is a filming amine, it will beattracted to and :adhere to the surface because of its natural aiinityfor metal. Otherwise any other coating will adhere to the surface of thepipe because of its nature. If the well is so deep that it isimpractical to introduce all the material at the bottom, additionalnozzles 16 may be 'located within the production string A intermediateof the bottom of the Well and the surface of the ground. They likewisecause a line -or atomized mist or spray to be introduced into the gasstream which is the gas being produced by the well.

At the surface of the ground additional nozzles 18 may be introducedthrough the distribution piping to introduce a iine or atomized mist orspray of corrosion inhibiting material which will coat the inside of theconduit.

Although this invention has been described for coating the insides ofconduits carrying petroleum gases it will be understood that it isadaptable for coating the insides of conduits carrying any gaseousmaterials. The specific rust or corrosion inhibitor would be thatadapted to prevent corrosion on the particular material of the conduitand the particular gas being carried by the conduit. By the termcorrosion is meant any sort of chemical deterioration which might takeplace including rusting and oxidation.

FIG. 2 illustrates certain modifications which may be made. Instead ofhaving a tube within the production string, it would also be possible tohave a tube 20 extend along the outside of the production string andenter the production string through side openings. Such construction iswell within the skill of persons familiar with the art.

Another modification illustrated in FIG. 2 is that 'mstead ofintroducing only corrosion inhibitor with conventional carriers orvehicles, a foaming agent is mixed into the materials introduced intothe tube. Such foam ing agents are well known to the art, as wvell asthe re ghting art and are produced by Champion Chemical, Inc. under thetrademark Foam'atron. By foaming agent we means a material which willmaintain the minute gas bubbles in the liquid and not necessarily themeans which introduces the bubbles into the liquid. The foaming agentmay be a combination of non-ionic water soluble compounds. Anotherexample of such :a foaming agent would be the Rohm & Haas trademarkedproduct Triton X- which is an alkylphenol wit-h 10 mol of ethylene oxideadduct.

When the materia-l issues from the nozzle, the gas striking the materialwill entrain a multitude of bubbles within it causing it to foam. Thecontinued flow of gas will carry the foam 22 upward in the productionstring bringing the inhibitor in contact with the surface of thevconduit thereby coating it. A typical example of such a desirablemixture is -as follows:

Initially rather ylarge amounts of the corrosion inhibitor are used toobtain the initial coating upon the conduit. Periodically thereafter,everyv three for four days, additional treatments :are made to renew thecoating.

It Will be apparent that the embodiments shown are only exemplary andthat various modiiications can be made in construction, materials, and'arrangements within the scope of the invention as `defined in theappended claims.

We claim -as our invention: y

1. The method of applying protective coatings to inside walls of gascarrying conduits comprising introducing a mixture of a polar filmingamine corrosion inhibitor, Water, and a foaming agent into the flowinggas stream -as the conduit is in normal use and entraining a multitudeof minute bubbles Within the mixture thereby causing the introducedmaterial to foam to the end that the inhibitor is carried by a foamyvehicle along the conduit.

2. The method of applying protective coatings to the production stringina gas well to protect it from connosion comprising the steps ofintroducing ya mixture of a polar filming amine y,corrosioninhibitor,Water, and a foaming agent into the production string at the bottom ofthe Well by means `of a tube extending to the surface, foaming saidmixture by entraining a multitude of minute bubbles Within the mixtureso that the inhibitor is carried by a foamy Ivehicle, and moving saidfoamy vehicle upward by the normal HOW of the owing gas being produced.v

3, The invention las dened'vin claim 2 wherein additional mixture Vofinhibitor, water, and foaming agent is introduced into the productionstring at points intermediate the bottom and surface.

References ouai in theme of this patent UNITED STATES PATENTS 1,602,190Eddy yet al. Oct. 5, 1926 2,357,559 Smith Sept. 5, 1944 2,460,259 KahlerJan. 25, 1949 2,673,817 Burns Mar. 30, 1954 2,839,465 Jones June 17,1958 OTHER REFERENCES Mills, R.V.A.: Protection of Oil and Gas FieldEquip- 4ment Against Corrosion, U.S. Bureau of Mines, Bulletin 233,1925, page. 82. t

Sluhan, C.A,: Wetting Agents, Their Structure, Characteristics, andUses, Paper Trade Journal, August 22,

1940; pages 26-3'1.

1. THE METHOD OF APPLYING PROTECTIVE COATINGS TO INSIDE WALLS OF GASCARRYING CONDUITS COMPRISING INTRODUCING A MIXTURE OF A POLAR FILMINGAMINE CORROSION INHIBITOR, WATER, AND A FOAMING AGENT INTO THE FLOWINGGAS STREAM AS THE CONDUIT IS IN NORMAL USE ENTRAINING A MULTITUDE OFMINUTE BUBBLES WITHIN THE MIXTURE THEREBY CAUSING THE INTRODUCEDMATERIAL TO FOAM TO THE END THAT THE INHIBITOR IS CARRIED BY A FOAMYVEHICLE ALONG THE CONDUIT.